The Life Cycle of a Frog

Frogs are amphibians, and this name suits them just fine. The reason for this is “amphibian” comes from the Greek words meaning “double life.” The lifestyle of a frog takes place both in the water and on land. First of all, a male and female clasp each other’s bodies in a tight embrace called amplexus. The male sits atop the female frog as it fertilizes the female’s eggs. The female frog lays several thousands of jelly-covered eggs (sometimes 10,000 or more) in the water. Frogs that lay their eggs in ponds usually form a clump of eggs called frogspawn. Eggs laid in streams are attached to the undersides of rocks, leaves, or are grouped in foam nests on the water. Depending on the weather, the eggs hatch into fish-like tadpoles at different timings. If the climate is warm, the eggs might hatch in one or two days. Cold weather might result in tadpoles hatching thirty to forty days after being laid. Some frogs do not watch over their eggs during their development. Since eggs and tadpoles are prone to being eaten by predators of the waters, I feel the frogs should definitely keep an eye on their offspring! Anyway, tadpoles have oval-shaped bodies and use gills to acquire oxygen from the water. They have a muscular tail with fins along its upper and lower portions for swimming. For its own safety, a tadpole often sticks onto vegetation in the pond until it is ready to break free and swim around the water. Their horny beak and rows of minuscule teeth help them consume algae for food. Some tadpole species even eat frog eggs and other tadpoles! In my opinion, it is appalling for an animal to eat its own kin. After a few weeks, the tadpoles begin to sprout one pair of legs and their tails begin to slowly be absorbed by the lysosomes of the amphibian. Now, they are called froglets. During this stage, the froglets lose their gills, grow lungs and a second pair of legs, develop long, sticky tongues in place of their tiny teeth, and go through changes in their heart and skeleton structures. Furthermore, the intestines in their digestive systems change to adapt to their new insect diet. Finally, the froglets become adult frogs during the last stage of their life. As soon as they are of reproductive age, the frogs produce more eggs, forming a new generation of amphibians!

Interested in gaining more knowledge about the frog's life cycle? Visit the Web sites that this information was based on:
http://encarta.msn.com/encyclopedia_761552464_2____5/Frog_(animal).html?partner=orp#s5
http://www.seagrant.wisc.edu/Frogs/frogs_life.html

The amplexus photo of this post is from:
http://biology.astate.edu/faculty/strauth/Publications.htm
The life cycle picture on this post was found on:
http://www.infovisual.info/02/029_en.html